The present invention relates to a heat-insulating mechanism for a compressor which introduces refrigerant gas from a suction pressure region into a compression chamber and discharges the refrigerant gas from the compression chamber to a discharge pressure region.
The temperature of refrigerant gas introduced from the outside of a compressor into a suction pressure region of the compressor influences the performance of the compressor. As the temperature of the refrigerant gas introduced into the suction pressure region rises, the density of the refrigerant gas to be introduced into a compression chamber reduces, with the consequence of deteriorated performance of the compressor.
In the compressor disclosed in Unexamined Japanese Patent Publication No. 2-264163, a rear cover forms therein a suction passage for introducing refrigerant gas therethrough into a suction chamber which is a part of a suction pressure region of the compressor, and a cylindrical conduit is inserted into the suction passage. The refrigerant gas is introduced into the suction chamber through an inner passage of the conduit.
When the amount of heat transmitted from the rear cover to the conduit is large, the temperature of refrigerant gas in the inner passage of the conduit rises, and the high-temperature refrigerant gas is introduced into the compression chamber through the suction chamber. This deteriorates the performance of the compressor. A clearance is formed between the outer peripheral wall surface of the conduit and the peripheral wall surface of the suction passage for controlling the heat transmitted from the rear cover to the conduit. However, the provision of the clearance alone is not enough to accomplish a high adiabatic efficiency. Therefore, there is a need for enhancing the adiabatic efficiency in the suction pressure region of the compressor.